Evidence of Sea Level Rise at the Early Ostionan Coralie Site (GT-3), c. AD 700, Grand Turk, Turks and Caicos Islands

Abstract

Soil and sediment analyses were conducted on samples from the early Ostionan Coralie Site (c.ad705±60) on Grand Turk, Turks and Caicos Islands, the earliest dated settlement site in the Bahama Islands. The focus of these analyses was a sand layer mantling archaeological features discovered on a buried land surface. The tapering, wedge-shaped configuration of the sand body prompted the hypothesis that it was deposited by water—either a storm surge or a more gradual rise in sea level. This hypothesis was tested using soil morphological descriptions, particle-size distribution analysis and grain characteristics, contents of organic carbon and total phosphorus, and identification of invertebrate organisms found in the soil samples. A fining upward trend in particle size, round and rolled grain shapes, and a rich shallow-water micro-invertebrate infauna indicated a gradual marine transgression over the site, as opposed to either a catastrophic storm event or aeolian deposition. These results explain the incremental inland shift of settlement activity over time at Coralie.